In a liquid crystal display device, a transverse field system is hitherto known as a system which applies an electric field to a liquid crystal layer. In a transverse field liquid crystal display device, a common electrode and pixel electrodes are provided on one substrate of a pair of substrates with a liquid crystal layer sandwiched therebetween, and an electric field in a substantially transverse direction (a direction substantially parallel to the substrates) relative to the liquid crystal layer is applied to the liquid crystal layer. In this case, since directors of liquid crystal molecules are not erected in a direction perpendicular to the substrates, there is an advantage that a viewing angle is widened. The transverse field liquid crystal display device includes an IPS (In-Plane Switching) liquid crystal display device and an FFS (Fringe Field Switching) liquid crystal display device which are different from each other in the electrode configuration.
The FFS liquid crystal display device generally includes a lower layer electrode which is formed on a substantially entire region in a pixel, and an upper layer electrode which is disposed above the lower layer electrode with an insulating film sandwiched therebetween and has a plurality of linear electrodes (for example, PTL 1). The FFS liquid crystal display device includes a type in which the lower layer electrode is used as a common electrode and the upper layer electrode is used as a pixel electrode, and a type in which the lower layer electrode is used as a pixel electrode and the upper layer electrode is used as a common electrode. In all cases, the pixel electrode and the common electrode overlap each other in plan view with the insulating film sandwiched therebetween, and pixel capacitance is formed in the overlapping portion.
In recent years, a liquid crystal display device has higher definition, and the pixel size tends to be smaller.
As described above, in the FFS liquid crystal display device, since the pixel capacitance is formed in the overlapping portion of the pixel electrode and the common electrode, the pixel capacitance decreases with the reduction in size of the pixel. If the pixel capacitance decreases, flickering or crosstalk is likely to occur, causing deterioration of display quality.